U niversity of Colorado freshman Lara Theobald walked out of the University of Colorado bookstore on the first floor of the University Memorial Center Thursday with $45 in hand -- not a small amount of money for a college student.

Theobald said it was nice to have some extra cash in her pocket as she prepares for her last week of the spring semester. However, the amount she received for her four textbooks was minimal compared to what paid to purchase them in January.

"I probably spent about $400 this semester," Theobald said. "My bio book alone was $150 and they only gave me $30 for it today, which is not great, but I guess it's better than nothing."

She also returned three books that she rented this spring, which is a simple drop-off. Theobald said in comparison to purchasing books, even though the rental books were cheaper at first, she likely won't follow that route next year since there's no return on the investment.

As finals began Saturday on campus, many students will be selling back textbooks this week in hopes of beginning the summer with a little more pocket change.

"Even if it's not much, I'd much rather get something back at the end of the semester than to just have to drop them off and walk out of here with nothing," Theobald said.

However, despite the low up-front cost of renting, a study of the top 1,000 textbooks used in the country from bigwords.com -- a price comparison service -- found that buying and selling textbooks actually ends up saving students an average of $56.64 per book.

The CU Book Store in the UMC began offering textbook rentals in the spring of 2010 and has increased its rental options every semester since.

Brian Groves, director of the CU Book Store, said they do not have intentions of decreasing rental options, as long as student interest remains.

"Our experience is that students are still very excited about rentals," Groves said. "We saw another significant increase in rentals last term and expect the same this fall."

Boulder resident Joe Hoppe started a price comparison website, rentscouter.com, about three years ago but said it's been difficult getting students to visit sites like his.

"I don't know why they're not using it, maybe they just don't know it's there, but I think they could benefit a lot from these sites," Hoppe said.

Price comparison sites like rentscouter.com, booksprice.com and bigwords.com, allow students to enter their textbook information -- and with one click, search several online vendors for the best prices in buying, renting or selling their books.

Hoppe said his site searches more than 40 vendors including Amazon, Chegg.com and Barnes and Noble. The highest buy-back offers are returned for the book and the student can choose their price from there.

While the sites don't typically include local stores like the CU Book Store, the Colorado Bookstore on the Hill or Shipping on the Hill, Hoppe said local shops only offer the best prices about 20 percent of the time, compared to online sites.

CU senior Rachel Epstein said she's never used a price comparison site and she likely never will, not just because she's about to graduate and won't likely be buying textbooks anytime soon, but because it's just a hassle.

"It's too much work to have to do that and check the stores and then decide, when you can just come in here (the CU Book Store) and get what you need all at once," Epstein said.

Over the past four years, Epstein said she's learned that the store on the Hill typically give students a little more money for their returned books, but that the book store in the UMC is the most convenient location.